1. Field of the Invention
The present invention relates to a measurement field of electronics and, more particularly, to a high sensitivity measurement device for measuring various parameters of non-electric quantity.
2. Description of the Prior Art
By utilizing the heat-sinking principle, based on the variation of the heat exchange nature of a measured object, the device and method for measuring various parameters of non-electric quantity have nowadays become important measures of electronics in the measurement of wind speed, flow rate, material composition, gas concentration, humidity, vacuum, heat conductivity, etc. The typical schemes are embodied in the instruments such as hot wire anemometer, hot film flowmeter, and heat conduction carbon oxide concentration tester, which have disadvantages of sensor easy to be damaged, large power dissipation, appreciable interference to the measured object, and difficulty of miniaturizing the instrument. However, until now there are no satisfactory arrangements to replace them. In recent years, the device and the method adopting semiconductor means acted as sensing element for carrying out above mentioned measurements have been presented. The typical arrangements of such can be known from U.S. Pat. No. 3,988,928, U.S. Pat. No. 3,992,940, etc., the main drawbacks of which are as follows: both the heating body and the temperature sensing element of the sensor are not located at the same spatial position, and it is necessary to perform the thermal coupling inside the sensor through an intermediate medium, so that the sensor has large heat inerts and is hard to obtain signals representing fast changing parameters of non-electric quantity. Besides, the fact that the heating process and the temperature measurement process affect each other not only reduces the measuring accuracy but also brings many difficulties to the signal processing. So far, it is difficult for the existing schemes to realize high responding speed, high sensitivity and high resolution measurements of wind speed, flow rate, material composition, gas concentration, humidity, vacuum, heat conductivity, etc. The instrument industries have been waiting for a new breakthrough related to the principle of measurement.